PHP's var_dump in JavaScript

How to use

You you can install via yarn add locutus and require this function via const var_dump = require('locutus/php/var/var_dump').

It is important to use a bundler that supports tree-shaking so that you only ship the functions that you actually use to your browser, instead of all of Locutus, which is massive. Examples are: Parcel, webpack, or rollup.js. For server-side use this is typically less of a concern.

Examples

Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#	code	expected result
1	var_dump(1)	'int(1)'
2	const simpleCircular = {} simpleCircular.self = simpleCircular var_dump(simpleCircular)	'array(1) {\n [self] =>\n Circular Reference Detected\n}\n'

Notes

• For returning a string, use var_export() with the second argument set to true

Here’s what our current JavaScript equivalent to PHP's var_dump looks like.

const visitedObjects = new Map() // Initialize a map to track visited objects

module.exports = function var_dump() {
  //  discuss at: https://locutus.io/php/var_dump/
  // original by: Brett Zamir (https://brett-zamir.me)
  // improved by: Zahlii
  // improved by: Brett Zamir (https://brett-zamir.me)
  //      note 1: For returning a string, use var_export() with the second argument set to true
  //   example 1: var_dump(1)
  //   returns 1: 'int(1)'
  //   example 2: const simpleCircular = {}
  //   example 2: simpleCircular.self = simpleCircular
  //   example 2: var_dump(simpleCircular)
  //   returns 2: 'array(1) {\n    [self] =>\n    Circular Reference Detected\n}\n'

  const echo = require('../strings/echo')
  let output = ''
  const padChar = ' '
  const padVal = 4
  let lgth = 0
  let i = 0

  const _getFuncName = function (fn) {
    const name = /\W*function\s+([\w$]+)\s*\(/.exec(fn)
    if (!name) {
      return '(Anonymous)'
    }
    return name[1]
  }

  const _repeatChar = function (len, padChar) {
    let str = ''
    for (let i = 0; i < len; i++) {
      str += padChar
    }
    return str
  }
  const _getInnerVal = function (val, thickPad) {
    let ret = ''
    if (val === null) {
      ret = 'NULL'
    } else if (typeof val === 'boolean') {
      ret = 'bool(' + val + ')'
    } else if (typeof val === 'string') {
      ret = 'string(' + val.length + ') "' + val + '"'
    } else if (typeof val === 'number') {
      if (parseFloat(val) === parseInt(val, 10)) {
        ret = 'int(' + val + ')'
      } else {
        ret = 'float(' + val + ')'
      }
    } else if (typeof val === 'undefined') {
      // The remaining are not PHP behavior because these values
      // only exist in this exact form in JavaScript
      ret = 'undefined'
    } else if (typeof val === 'function') {
      const funcLines = val.toString().split('\n')
      ret = ''
      for (let i = 0, fll = funcLines.length; i < fll; i++) {
        ret += (i !== 0 ? '\n' + thickPad : '') + funcLines[i]
      }
    } else if (val instanceof Date) {
      ret = 'Date(' + val + ')'
    } else if (val instanceof RegExp) {
      ret = 'RegExp(' + val + ')'
    } else if (val.nodeName) {
      // Different than PHP's DOMElement
      switch (val.nodeType) {
        case 1:
          if (typeof val.namespaceURI === 'undefined' || val.namespaceURI === 'https://www.w3.org/1999/xhtml') {
            // Undefined namespace could be plain XML, but namespaceURI not widely supported
            ret = 'HTMLElement("' + val.nodeName + '")'
          } else {
            ret = 'XML Element("' + val.nodeName + '")'
          }
          break
        case 2:
          ret = 'ATTRIBUTE_NODE(' + val.nodeName + ')'
          break
        case 3:
          ret = 'TEXT_NODE(' + val.nodeValue + ')'
          break
        case 4:
          ret = 'CDATA_SECTION_NODE(' + val.nodeValue + ')'
          break
        case 5:
          ret = 'ENTITY_REFERENCE_NODE'
          break
        case 6:
          ret = 'ENTITY_NODE'
          break
        case 7:
          ret = 'PROCESSING_INSTRUCTION_NODE(' + val.nodeName + ':' + val.nodeValue + ')'
          break
        case 8:
          ret = 'COMMENT_NODE(' + val.nodeValue + ')'
          break
        case 9:
          ret = 'DOCUMENT_NODE'
          break
        case 10:
          ret = 'DOCUMENT_TYPE_NODE'
          break
        case 11:
          ret = 'DOCUMENT_FRAGMENT_NODE'
          break
        case 12:
          ret = 'NOTATION_NODE'
          break
      }
    }
    return ret
  }

  const _formatArray = function (obj, curDepth, padVal, padChar, visitedObjects) {
    if (curDepth > 0) {
      curDepth++
    }

    const basePad = _repeatChar(padVal * (curDepth - 1), padChar)
    const thickPad = _repeatChar(padVal * (curDepth + 1), padChar)
    let str = ''
    let val = ''

    if (typeof obj === 'object' && obj !== null) {
      if (visitedObjects.has(obj)) {
        // Circular reference detected, return a placeholder or a message
        return 'Circular Reference Detected\n'
      } else {
        // Mark this object as visited by adding it to the map
        visitedObjects.set(obj, true)
      }

      if (obj.constructor && _getFuncName(obj.constructor) === 'LOCUTUS_Resource') {
        return obj.var_dump()
      }
      lgth = 0
      for (const someProp in obj) {
        if (obj.hasOwnProperty(someProp)) {
          lgth++
        }
      }
      str += 'array(' + lgth + ') {\n'
      for (const key in obj) {
        const objVal = obj[key]
        if (
          typeof objVal === 'object' &&
          objVal !== null &&
          !(objVal instanceof Date) &&
          !(objVal instanceof RegExp) &&
          !objVal.nodeName
        ) {
          str += thickPad
          str += '['
          str += key
          str += '] =>\n'
          str += thickPad
          str += _formatArray(objVal, curDepth + 1, padVal, padChar, visitedObjects)
        } else {
          val = _getInnerVal(objVal, thickPad)
          str += thickPad
          str += '['
          str += key
          str += '] =>\n'
          str += thickPad
          str += val
          str += '\n'
        }
      }
      str += basePad + '}\n'
    } else {
      str = _getInnerVal(obj, thickPad)
    }
    return str
  }

  output = _formatArray(arguments[0], 0, padVal, padChar, visitedObjects)
  for (i = 1; i < arguments.length; i++) {
    output += '\n' + _formatArray(arguments[i], 0, padVal, padChar, visitedObjects)
  }

  echo(output)

  // Not how PHP does it, but helps us test:
  return output
}

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we assimilate first iterations with imperfections, hoping for others to take issue with-and improve them. This unorthodox approach has worked very well to foster fun and fruitful collaboration, but please be reminded to use our creations at your own risk. THE SOFTWARE IS PROVIDED "AS IS" has never been more true than for Locutus.

Now go and: [ View on GitHub | Edit on GitHub | View Raw ]

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